1. Field of the Invention
The present invention relates to an ophthalmic measuring apparatus, and particularly to an ophthalmic measuring apparatus for obtaining an optical characteristic of a subject eye by processing plural Hartmann images.
2. Description of the Related Art
In recent years, an optical equipment used for medicine becomes popular, especially in ophthalmology, as an optical characteristic measuring apparatus for examining eye functions, such as eye refraction and adjustment, and the inside of the eye. For example, there exists an apparatus called a photo-refractometer for obtaining the refraction of the subject eye and the retina shape (for example, see patent document 1: Japanese Patent Application No. 2000-351796). The patent document 1 discloses an optical characteristic measuring apparatus which acquires a Hartmann image from a light receiving part, calculates Zernike coefficients on the basis of a distance between a Hartmann plate and the light receiving part, coordinates and the like, calculates the wavefront of the subject eye on the basis of the Zernike coefficients, and displays measurement data, image data corresponding to measurement results, and numerical data. Besides, there is disclosed an apparatus for measuring spherical refractivity, a degree of astigmatism, an astigmatic axial angle and the like from image data of a target image projected on the retina of the subject eye (for example, see patent document 2: Japanese Patent No. 2580215). Incidentally, in the measurement results of these various tests, for example, it becomes important that the subject eye of a patient as a test object is placed under what measurement conditions.
However, in the conventional measuring apparatus for measuring aberrations of the subject eye, in the case where there is a large difference in the distribution of an eye characteristic, such as an eye refractive index, refraction or aberration, there is a case where the measurement can not be made. The large difference like this can occur by, for example, a disease, an injury, a surgical operation or the like.